title: A novel automated alternating current biosusceptometry method to characterization of controlled-release magnetic floating tablets of metronidazole.
abstract: BACKGROUND
  Alternating Current Biosusceptometry is a magnetically method used to characterize drug delivery systems. This work presents a system composed by an automated ACB sensor to acquire magnetic images of floating tablets.
  
  
  OBJECTIVE
  The purpose of this study was to use an automated Alternating Current Biosusceptometry (ACB) to characterize magnetic floating tablets for controlled drug delivery.
  
  
  METHODS
  Floating tablets were prepared with hydroxypropyl methylcellulose (HPMC) as hydrophilic gel material, sodium bicarbonate as gas-generating agent and ferrite as magnetic marker. ACB was used to characterize the floating lag time and the tablet hydration rate, by quantification of the magnetic images to magnetic area. Besides the buoyancy, the floating tablets were evaluated for weight uniformity, hardness, swelling and in vitro drug release.
  
  
  RESULTS
  The optimized tablets were prepared with equal amounts of HPMC and ferrite, and began to float within 4 min, maintaining the flotation during more than 24 h. The data of all physical parameters lied within the pharmacopeial limits. Drug release at 24 h was about 40%.
  
  
  CONCLUSIONS
  The ACB results showed that this study provided a new approach for in vitro investigation of controlled-release dosage forms. Moreover, using automated ACB will also be possible to test these parameters in humans allowing to establish an in vitro.in vivo correlation (IVIVC).
authors.affiliation: Department of Physics and Biophysics, Bioscience Institute, São Paulo State University - UNESP , Botucatu, SP , Brazil and.
authors.forename: Priscileila Colerato
authors.initials: PC
authors.lastname: Ferrari
authors.forename: Dany Bruno Borella
authors.initials: DB
authors.lastname: dos Santos Grossklauss
authors.forename: Matheus
authors.initials: M
authors.lastname: Alvarez
authors.forename: Fabiano Carlos
authors.initials: FC
authors.lastname: Paixão
authors.forename: Uilian
authors.initials: U
authors.lastname: Andreis
authors.forename: Alexandre Giordano
authors.initials: AG
authors.lastname: Crispim
authors.forename: Ana Dóris
authors.initials: AD
authors.lastname: de Castro
authors.forename: Raul Cesar
authors.initials: RC
authors.lastname: Evangelista
authors.forename: José Ricardo
authors.initials: JR
authors.lastname: de Arruda Miranda
mesh_terms: D003692:Delayed-Action Preparations / Q000737:chemistry*; D016503:Drug Delivery Systems / Q000379:methods; D065546:Drug Liberation; D005079:Excipients / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D005782:Gels / Q000737:chemistry; D006244:Hardness; D006801:Humans; D065347:Hypromellose Derivatives / Q000737:chemistry; D008280:Magnetics / Q000379:methods*; D008795:Metronidazole / Q000737:chemistry*; D017693:Sodium Bicarbonate / Q000737:chemistry; D013607:Tablets / Q000737:chemistry; D013678:Technology, Pharmaceutical / Q000379:methods*
chemical_list: D003692:Delayed-Action Preparations; D005079:Excipients; D005290:Ferric Compounds; D005782:Gels; D013607:Tablets; C001215:ferrite; D008795:Metronidazole; D065347:Hypromellose Derivatives; D017693:Sodium Bicarbonate
keywords: Biosusceptometry; controlled drug release; floating tablets; magnetic marker; swelling